Screening of Anthraquinones and Assessment of Antimicrobial Activities of Ethanol Extracts of AdansoniadigitataL., Sudan

The aim of the study was to investigate anthraquinones and to determine the antimicrobial activity of different extracts of Adansonia digitata L. , a plant used by Sudanese communities to treat various ailments such as diarrhea and microbial infections. The anthraquinones were screened qualitatively. The presences of anthraquinones were detected in ethanol extracts along with acetone and ethyl acetate fractions of both fruits fibers and fruits cover of A. digitata. The fruits fibers and fruits cover extracts were screened for antimicrobial activity against Gram- positive (Bacillus subtilis and Staphylococcus aureus), and Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris and Klebsiella pneumoniae), and two fungi (Candida albicans and Aspergillus niger) using agar well diffusion method. Results showed that the fruits covers extract was exerted highest activity on bacterial agents tested compared to fruits fibers extract, and fruits fibers extract was the most effective against fungi (A. niger), while both extracts were not active against C. albicans. Fruits cover extract at concentration of 100 g / ml showed 25 mm diameter zone of inhibition against P. vulgaris. This was followed by 23, 22 and 21 mm zone of inhibition against B. subtilis, K. pneumoniae and S. aureus. TLC analysis revealed the presence of two anthraquinones compounds in the acetone extract of the fruits cover.